为什么回调函数的名称回调？

Question

please don't care or go strict on correcting the syntax. The point more important is why is the name callback for the callback function?

for example:-

function drive(int x, int y);
function breaker(int x, int y, callbackFunction);
int function main(){
    drive(23,24); // why is this called a "call to a function"?
    breaker(23,45,drive); // why "drive" here is called a callback and why not "call to function" like other function.
}

function drive(int x, int y){
   printf("%d%d",x,y);
}

function breaker(int x, int y, callbackFunction){
  callbackFunction(x,y);
}

The point here is not the accuracy of syntax. The point is i am calling the "drive" in main method and that is called as "calling the function" and when i pass the "drive" function as an argument to other function in "breaker" the "drive" is called as callback but why? any call to function have to refer to function and should execute it but why the difference in names?

Answer 1

breaker(23,45,drive); // why "drive" here is called a callback and why not "call to function" like other function.

This does not call drive() . This is a call to breaker with the address of the function drive as a parameter. The abscence of parenthesis denotes that we are not calling drive, we are passing the address of the function as a parameter.

The purpose of doing so is so that breaker() can call drive() as many times at it needs.

Edit:

The name callback is because the functions you are calling is calling your function back. This is more evident when the function with a callback parameter is provided by someone else.

Take the qsort function for instance. qsort is a standard C function that takes a comparator callback function and an array to sort. You call qsort() and qsort() calls your comparator whenever it needs to compare two elements in the array. So a standard C function calls back to your code.

Answer 2

breaker(23,45,drive); 

this will replace callbackFunction with drive

function breaker(int x, int y, drive){
   drive(x,y);
}